Certain technological advances have recently been applied to previously-accepted medical treatments of maladies of the spine. These technological advances have significantly facilitated the treatment of these spinal difficulties.
Specifically, these new treatments involve the use of scopes or cannulas placed into the spine and small porous bags filled with bone chips to treat fractures of the spine and to fuse individual bone segments of the spine together. These bags are porous to allow ingrowth from adjacent bone and thereby join the bone segments.
There are certain problems with these prior art bags of bone chips for treating spinal maladies. If the bag is placed in the disc space, the exposed pores on the sides of the bag may allow the passage of body fluids through the pores into the bag. These bodily fluids have the opportunity to digest, soften, and change the non-compressive strength of the bag, thereby causing premature collapse before bone fusion has completed.
There are also uncertainties regarding an optimum size of the bag to be used. For example, if a surgeon wishes to place the bag in the disc space, there are uncertainties regarding the desired size, shape, and height of the bag.
Finally, there are issues regarding optimum orientation of the bag in the area to be fused, and assessment of proper orientation in position.
U.S. Pat. No. 5,571,189 discloses an expandable, porous fabric implant or bag for insertion into the interior of a reamed out disc which is packed with material to stabilize the spinal segment. The fabric pores allow for tissue ingrowth through the implant. A drawback to this bag is that bodily fluids can enter the porous sides of the bag and thereby digest or partially digest inserted bone graft material before fusion has completed, and thereby potentially causing failure of the implant or graft.